| // Copyright 2020 The Fuchsia Authors |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #include <lib/unittest/unittest.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| namespace { |
| |
| constexpr size_t kStackAlignment = 16; |
| |
| // The frame pointer is the SP after pushing two words. |
| // This differs mod 16 when using 32-bit words (x86-32). |
| constexpr size_t kFpAdjust = 2 * sizeof(uintptr_t); |
| |
| bool StackAligned(void* ptr, bool fp) { |
| // Make sure the compiler doesn't think it knows the value, |
| // so there will be a runtime check. |
| uintptr_t stack_addr; |
| __asm__("" : "=g"(stack_addr) : "0"(ptr)); |
| if (fp) { |
| stack_addr += kFpAdjust; |
| } |
| return stack_addr % kStackAlignment == 0; |
| } |
| |
| bool stack_alignment() { |
| BEGIN_TEST; |
| |
| void* machine_stack = __builtin_frame_address(0); |
| EXPECT_TRUE(StackAligned(machine_stack, true)); |
| |
| #if __has_feature(safe_stack) |
| alignas(kStackAlignment) char unsafe_stack[1] = {17}; |
| EXPECT_TRUE(StackAligned(unsafe_stack, false)); |
| #endif |
| |
| END_TEST; |
| } |
| |
| } // namespace |
| |
| UNITTEST_START_TESTCASE(stack_tests) |
| UNITTEST("stack alignment", stack_alignment) |
| UNITTEST_END_TESTCASE(stack_tests, "stack", "stack tests") |
